#183A75
Closest named color: Marine Blue (#01386A). oklch(35.9% 0.109 260.6), rgb(24, 58, 117).
Aa
White text reads best on this color (11.04:1).
About this color
#183A75 is a dark, moderately saturated blue. In OKLCH its lightness is 36%, its chroma 0.109 and its hue 261°. Its hue sits on the cool side of the wheel. The nearest named color is Marine Blue (#01386A), ΔE 0.026 away. White text reads best on it, at 11.04:1.
| Hue family | Blues |
| Lightness | dark (36%) |
| Chroma | moderately saturated (0.109) |
| Temperature | cool |
| Nearest name | Marine Blue (#01386A) |
| Black text | 1.90:1 |
| White text | 11.04:1 |
Values
| HEX | #183A75 |
| RGB | rgb(24, 58, 117) |
| HSL | hsl(218, 66%, 28%) |
| OKLCH | oklch(35.9% 0.109 260.6) |
Contrast
WCAG 2 contrast ratios are the conformance target: AA needs 4.5:1 for body text and 3:1 for large text, AAA needs 7:1. APCA Lc values are supplementary guidance from the WCAG 3 drafts.
| Pair | WCAG 2 | Result | APCA | APCA guidance |
|---|---|---|---|---|
| White text on #183A75 | 11.04:1 | AAA | Lc -99.1 | Preferred for body text |
| Black text on #183A75 | 1.90:1 | Fails | Lc 8.7 | Not readable |
| #183A75 text on white | 11.04:1 | AAA | Lc 95.2 | Preferred for body text |
| #183A75 text on black | 1.90:1 | Fails | Lc -7.5 | Not readable |
Tints and shades
A 50–950 scale built in OKLCH: the hue is held, lightness follows a Tailwind v4-like curve, and every step is kept inside the sRGB gamut. This color sits at step 900.
-
Step 50
50
#F1F6FD
oklch(97.1% 0.011 256.7)
-
Step 100
100
#E1EAFA
oklch(93.5% 0.024 262.1)
-
Step 200
200
#C8DAF8
oklch(88.4% 0.046 260.7)
-
Step 300
300
#A3C2F6
oklch(81% 0.081 260.6)
-
Step 400
400
#70A0F2
oklch(70.7% 0.132 260.6)
-
Step 500
500
#4A86ED
oklch(63.1% 0.167 260.5)
-
Step 600
600
#2D6DDB
oklch(55.6% 0.181 260.5)
-
Step 700
700
#205ABE
oklch(49% 0.169 260.6)
-
Step 800
800
#1C4A9A
oklch(42.6% 0.14 260.7)
-
Step 900
900 (this color)
#183A75
oklch(35.9% 0.109 260.6)
-
Step 950
950
#112548
oklch(26.9% 0.07 260.7)
#183A75 with color blindness
Simulated with the Machado et al. (2009) model. ΔE is how far the color moves: below about 0.02 you would not notice a change.
| Vision | Seen as | Shift (ΔE) |
|---|---|---|
| Protanopia (no red cones) | #194077 | 0.018 |
| Deuteranopia (no green cones) | #003874 | 0.017 |
| Tritanopia (no blue cones) | #004852 | 0.084 |
| Achromatopsia (no color) | #3C3C3C | 0.109 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #183A75
#183A75
oklch(35.9% 0.109 260.6)
- #513800
#513800
oklch(36% 0.074 80.6)
Analogous
Neighbouring hues, 30° either side.
Split complementary
The two hues beside the complement (150° and 210°).
Triadic
Three hues spaced 120° apart.
Palettes with this color
Curated palettes that contain a color within ΔE 0.04 (OKLab) of #183A75, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Marine Blue #01386A ΔE 0.026
- Twilight Blue #0A437A ΔE 0.026
- Prussian Blue #1D3557 ΔE 0.052
- Marine #042E60 ΔE 0.054
- Cobalt #1E488F ΔE 0.058
- Light Navy #155084 ΔE 0.067
- Dark Grey Blue #29465B ΔE 0.067
- Dark Blue Grey #1F3B4D ΔE 0.071
Use #183A75 in your product
Turn it into light and dark UI roles checked for contrast, then export to Tailwind v4, shadcn/ui, CSS or design tokens.